This disclosure relates to medical devices and more particularly to an implantable lead.
The medical device industry produces a wide variety of electronic and mechanical devices for treating patient medical conditions such as pacemakers, defibrillators, neurostimulators and therapeutic substance delivery pumps. Medical devices can be configured to be surgically implanted or connected externally to the patient receiving treatment. Clinicians use medical devices alone or in combination with therapeutic substance therapies and surgery to treat patient medical conditions. For some medical conditions, medical devices provide the best and sometimes the only therapy to restore an individual to a more healthful condition and a fuller life. One type of medical device is an implantable neurological stimulation system that can be used to treat conditions such as pain, movement disorders, pelvic floor disorders, gastroparesis, and a wide variety of other medical conditions. The neurostimulation system typically includes a neurostimulator, a stimulation lead, and an extension such as shown in Medtronic, Inc. brochure “Implantable Neurostimulation System” (1998). More specifically, the neurostimulator system can be an Itrel II® Model 7424 or an Itrel 3® Model 7425 available from Medtronic, Inc. in Minneapolis, Minn. that can be used to treat conditions such as pain, movement disorders and pelvic floor disorders. The neurostimulator is typically connected to a stimulation lead that has one or more electrodes to deliver electrical stimulation to a specific location in the patient's body.
Implantable lead having multiple conductors typically require that each conductor be electrically insulated from the other conductors and each conductor can be assessed at an appropriate location in the implantable lead for forming a connection with a contact. Some implantable leads use electrically insulating conductor coating to electrically isolate the conductors, but electrically insulating conductor coatings can have dielectric limitations. Other implantable leads have used separate lumens for each conductor and the stylet to electrically isolate the conductors. However, implantable lead with separate conductor lumens can be difficult to manufacture particularly with regard to accessing the conductor through an appropriate location in the implantable lead outer surface for forming a connection with a contact. An example of a lead with multiple lumens is shown in U.S. Pat. No. 6,181,971 “Joining Conductor Cables And Electrodes On A Multi-Lumen Lead Body” by Doan (Jan. 30, 2001). An example of a lead is shown in U.S. Pat. No. 6,216,045 “Implantable Lead And Method Of Manufacture” by Black et al. (Apr. 10, 2001).
For the foregoing reasons, there is a need for an implantable lead with improved conductor lumens to separate and insulate conductors while also permitting access to conductors through the implantable lead outer surface.